Driving arrangement for rolling mills or for the mechanical transmission of power from electric motors



Nov. 17, 1925- A. BOAS DRIVING ARRANGEMENT FOR ROLLING MILLS on FOR THE MECHANICAL TRANSMISSION OF POWER FROM ELECTRIC uo'rons Filed Jan. 5. 1924 Patented Nov. 17, 1925. i UNITED STATES PATENT OFFICE.

ANDRE BOAS, or PARIS, FRANCE, ASSIGNOLR. TO SOCIETE ANONYME nus ENGRENAGES CITROEN, or PARIS, FRANCE, A CORPORATION or FRANCE.

DRIVING ARRANGEMENT FOR ROLLING MILLS OR FOR THE MECHANICAL TRANS- MISSION OF POWER FROM ELECTRIC MOTORS.

Application filed January 3, 1924 Serial No. 684,24A.

To all whom it may concern. without, however, considering the maximum 5 Be it known that I, ANDRE BoAs, citizen of economy in the sale price of the motor.

of the French Republic, residing at Paris, In the construction of electric motors, the Department of the Seine, in France, and value of the linear speed to the induction 5 having I 0. address 31' Quai de Grenelle, plays, as is wellknown, an important funcin the said city, have invented certain new tion. IVhen the motor is of relatively 60 and useful Improvements in Driving An slight dimensions and power it is quite posrangements for Rolling Mills or for the sible to adopt moderately high linear speeds, Mechanical Transmission of Power from the laminations of the rotor being in one Electric Motors; and I do hereby declare piece and secured directly on the shaft.

the following to be a full, clear, and exact But when the dimensions of the motor in- 65 description of the invention, such as will crease the linear speed is limited by the enable others skilled in the art to which it effect of the centrifugal force acting on the appertains to make and use the same. sheet metal segments and on the rigid wind- The present invention relates to certain ings of the rotor.

driving arrangements for rolling mills or The object of the present invention con- 70 for the mechanical transmission of power, sists in utilizing this fact with a view of having the same characteristics which elimian economical construction for driving a nate to a considerable extent the difliculties rolling mill, the arrangement being such of effecting such transmission when derived that the rotor itself serves as the flywheel from electric motors. The motor of which the rotor then forms the 75 The actual conditions of the art may be fly wheel 1s analogous in its general arfairly resumed as follows rangement to fly wheel alternators which When the rolling mills, for example, are have been heretofore constructed with the to be driven by electric motors, one is comview of direct coupling w th steam engines polled either to have recourse to direct drive at constant speed. That IS to say, the 1nby a motor the number of revolutions of duction surfaceis a cylinder of large diamwhich corresponds to that of the rolling eter and ofshght thickness. In these mamill and the price of which is extre ely chines the linear speed relatively to the inhigh, or to employ a motor capable of roduction was relatively slight, the necessities tating at normal speed for its power and for of transport limiting the diameter. I But H a normal price, which motor is utilized the number of revolutions is not fixed by to drive the shaft of the rolling mill by that of the steam engine the linear speed means of one or more than one train of relatively to the induction and consequently gearing. By reason of the irregularity of the inertia of the motor can be considerably the work required which changes suddenly increased because the parts which serve to from zero to a very considerable maximum secure the laminations are attached very a fly wheel is always necessary so as to obclose to the 1nduct1on surface and thus intain considerable economy if the rolling crease the moment of inertia. At the same 40 ill b ot ibl Thi fly wh l can time the space occupied by the fly wheel be placed either on the shaft of the rolling forming rotor in the chrection of the length mill or on that of the motor which rotates of the shaft is no greater than that which at high speed. In this latter arrangement 1t would have occupied as a separate and a considerable amount of energy is accumudistinct fly wheel and consequently the lated with a lighter fly wheel. But the flexure of the shaft can be great. Finally, load on the shaft bearings of the motor and the direct connection of the rotor to the of the fly wheel then increases and the first pinion of the train of gearing which design of these hearings offers considerable is disposed adjacent thereto has the advandifliculty when the speed of the motor is tage of saving the shaft from all fatigue great by reason of the co-relative increase due to torsion. Further, a symmetrical arin the coefficient of friction. One is thererangement of the installation ensures the fore compelled in the choice of the motor absolute equality in value and in direction speed to prefer a motor which by reason of of the load on the bearings. its number of revolutions will be economical The accompanying Figures 1 to 3 shewn diagrammatically relate to a sheet metal rolling mill, for example, and indicate:

Figure 1 shows a plan partly in section of an installation comprising a driving arrangement in accordance with the present invention, the rolling mill being driven by two electric motors.

Figure 2 is an elevation of Figure 1.

Figure 3 1s sectional plan of a modified installation in accordance with the invention in which a single electric motor is used.

Referring to Figures 1 and 2, the rotors of the two motors are indicated. at l, the said rotors being situated one on each side of a pinion 2 indicates the stators of the two motors. The shaft of the t *0 meters is indicated at 4, the said shaft being also common to the pinion 3. The bearings of the shaft are indicated at -53, 5, and 6 is a gear wheel driven ,by the pinion 8. The shaft 7 of the gear wheel 6 is connected to the rolling mill by couplings. 8, 8 are the bearings for the shaft 7. The base plate 9 carries the four bearings 5, 5, 8, 5 and the stators 2, 2.

The pinion 3 is provided with end flanges l0, l) on which are fixed the rotor discs ll, 11 by means of bolts 12, the pitch circle and the number of which are suflicient to afford perfect safety coupled with the addition of rings or keys. In this manner, the driving of the pinion is effected mainly by these bolts from both sides of the pinion instead of being effected by a key on the shaft acting on a small diameter and subjecting the shaft to torsion.

Referring now to the modification sh'ewn in Figure 3, it is here supposed that in place of a single pinion and one motor there are two pinions as shewn at 3, 3 each driving a wheel 6 keyed on the shaft 7 of a train of rolling mills, there being shewn only a single motor of which the rotor forming a fly wheel is placed at the centre. The connection of each of the pinions 3, 3 and the rotor is effected in the same manner in the arrangement shown in Figure 1. The other parts are the same and bear the same reference numerals as Figures 1 and 2. As will be readily seen from an examination of Figure 3, sy'mnretry is again re'aliz'c'd in this arrangement and consequently the bearings under all conditions are subjected to equal loads.

On the drawings there is shewn trains of gearing having straight teeth but double helical, herringbone or other suitable gearing could also be employed.

It will be obvious to any expert in the art to which the invention relates that the application of the present invention, which is specially applicable in the case of the driving of rolling mills, could also be used in all cases for the transmission of power from an electric motor to a shaft which is to be rotated at reduced speed and on which the resistant couple "is subjected to considerable and continual variations, whether of a periodic or aperiodic nature and which usually require the addition of a regulating fly wheel of which the mass according to the present invention would conflict with that of the 'rotor of the motor.

hat I claim is:

l. The combination of an electric motor having its rotor revolubliy mounted on a stationary shaft and serving as a fly wheel, a pinion revoluble on said shaft, flanged connections between said rotor and said pin ion, and a driven gear meshing with said pinion. V

2. The combination of two electric motors having their rotors revolubly mounted in spaced relation on a stationary shaft and serving as fly wheels, a pinion revolubl'y mounted on said shaft between said rotors, flanged connections between said pinion and said rotors, and a driven gear meshing with said pinion.

In testimonywhereof I affix my signature.

ANDRE BOAS. 

